Computer Turning off and on at different short intervals

[Morizan]

Hi, I have a custom built pc that i've had around 3.5 years, the other day the computer started the shutdown process (windows trying to close programs to shutdown) I cancelled the shutdown, but it just comes up again. After the computer shuts down, it restarts itself not instantly, but soon after. It continues in this cycle, but sometimes I can get to the desktop and stay on for a few minutes, sometimes it shuts down before the login screen. It still shuts down in safe mode as well. Not sure on how much this could affect it, but when I am able to get to the desktop chrome auto-opens and brings me to a russian GTAV page, any help would be appreciated, thinking it's a power supply or motherboard error with the cycling :/

Offhand I know these specs..
i5-760 2.8ghz
8gb ram
nvidia evga gtx 660ti
1tb hard drive

 

[tsnor]

Download and run bootable norten anti-virus = free download. rule out most malware.

Downlaod and run a bootable memory test (e.g. ultimate boot CD). The bootable part is important, it gets rid of your windows as a cause for the re-boot. If it runs cleanly suspect software problems.

If you get a fail running the bootable memory test - post it. If it runs clean post that too. The actions you will take are different.

 

[Morizan]

Thanks, I'll try those suggestions out tonight after work, one other thing I forgot to mention, computer bluescreened one of the times I continually declined the shutdown.

 

[Morizan]

So i tried running it with 2 of the 4 ram sticks, worked fine, no more issues, tried with the other two, still worked fine, i was thinking it was a bad stick.. I put all 4 back in, when the computer started there was a small spark and a minor burning smell, now I don't get any display with any ram sticks in or out.. motherboard goes through 3 red light step process before starting.. now it only gets to the 2nd red light near the ram and stays on.. any ideas? 🙁

 

[tsnor]

Ouch. physically unplug PC. A computer power on/off butter does not actually do anything to the power to the computer, it's just a signal to the MB to start a boot. I would not plug power back in until you think you've found the problem.

I'm not the best guy to find a short. Suggest open a new thread with title like "swapped dimms, then spark on power on and burnt smell" then include your description. put a pointer back to this thread so no-one thinks you are double posting.

Physically inspect the dimms and the dimm slot. See if they show signs of burning/scorching. They may not. IF they do then see what might have caused the short (fail on the dimm or gunk in the dimm slot)

Now start hunting in your case for a short. For example a wire with a missing piece of insulation may have touched the case. You may have pushed wires around as you swapped DIMMS. Hopefully there will be some smell or black marks to help you find it. It could be pinched wires behind the MB that finally wore through after 3 years of rubbing. (p.s. you did exactly right to swap the dimms, that is good diagnostic procedure. if doing that fried the mb or PSU that's not on you, it's on the failed HW). You need to find the cause of the short before you start replacing parts or you will burn up more equipment. For example, I would not test those dimms in a new MB. Likely you will need to remove MB and PSU from case to find problem if its not the dimms.

Inspect the PSU visually, and sniff it, but do not open it. Shock risk even when unplugged and nothing to fix if you open the PSU case. If anything in the PSU looks bad strongly consider replacing it. Note that the PSU will have sucked any burning smell in through its fan, so it may have a smell even if it did not burn.

If you removed the MB, CPU and PSU from case suggest you breadboard them on a cardboard box, no other parts. Use compressed air to blow anything out of the dimm slots. Then power up to get to the "no memory beep - or in your MB's case I think from your appends that's the 2 light diagnostic but did not check manual. Then I'd try a dimm to see if I could get it to post no video. Then keep adding parts back in until it works. If you can't get it past two lights then it's time to see if you want to buy new memory or new MB or both. Or if you want to get a new generation MB, CPU and Memory. I still use i7-920 so know i5-760 is not slow however if you find you need to buy parts a nice current gen i5, MB, memory bundle is around $400 with cheaper available. For example http://www.tigerdirect.com/applications/category/category_slc.asp?CatId=11497)

 

[Morizan]

So based on testing at my friend's place, we determined the motherboard needed to be replaced, visible damage going from the ram slot to a capacitor. Bought a new mini-atx motherboard and amd six core processor, somehow I was able to keep running what I had on the hard drive with this new setup instead of having to reformat. I noticed a major issue though, the plug casing for the power supply wiggles and literally will shut the computer off instantly over and over if it's not held in an upright position, I have a bungee cord holding it as temporary solution, but the computer still attempts the shutdown process every 15 minutes or so, do you think the power supply is still causing this, and it's just a major short that's getting partially fixed by holding it upright?

 

[tsnor]

I'm a wimp when it comes to possible fires and shock hazard.

"..I noticed a major issue though, the plug casing for the power supply wiggles and literally will shut the computer off instantly over and over if it's not held in an upright position, I have a bungee cord..." This would scare me. Thats the 120V input and a loose connection gets hot.

Often a "wiggle the cord" problem is the electric cord at entry to the plug has been bent often enough to have a break. If so the cord may be very hot there and may shock you if you touch it. Unplugged it's safe. IF it's not the cord then the wires/parts inside the PSU might be partially unattached, which might explain the sparks and fried motherboard. Note people report the X capacitor used in a power supply's transient filter stage across the AC input is a serious shock hazard so even unplugged if there are loose parts in the PSU you don't want to try to fix.

Suggest you try a different power cord (so many things use this standard cord that you can borrow on from someone easily or you may have a spare). IF the new power cord did not completely, obvisously solve the problem I'd junk the PSU and get a new one that had a good review at hardwaresecrets.com or similar site that actually tears down and tests PSUs.

 

[Morizan]

Could be the what caused the motherboard to fry, mainly i'm wondering if the loose connection can cause the power supply to not send enough power to the rest of the computer. It's not the cord itself causing the problem, but the loose socket within the power supply. I want to be sure, if the computer isn't recieving enough power and you attempt do something that requires more power than you have, does the computer go into 'attempting to shutdown windows' or would it just power off instantaneously? Plan on getting a new power supply when I get home today, i'll mark your answer down if that solves the issue, thanks for the help

 

[tsnor]

Power from PSU goes to voltage regulators on MB (and recently CPU) and video card. I'd guess they'd hold up voltage as long as their caps can, then you'd get a power off like you pulled the line cord from wall. If for some reason the MB (CPU) and video card voltage regulators gave low voltage then instructions could fail giving blue screen or just bad results (think CPU and video overclocking artifacts). That could include sudden shutdowns and blue screens as well as other sorts of errors.

I'd be more worried about the PSU putting too much voltage onto one of its DC outputs -- that would match with a spark and scorch marks on your MB. Like a loose component in the PSU shorting 120V onto one of the DC outputs.

Glad you are getting a new PSU, I would not use the old one at all again.

 

[Morizan]

Installed new PSU, everything seemed to be working fine.. then after about an hour it went back to attempting to shutdown frequently again. I'm confused, it shuts down even booting from a secondary drive, is the only thing left the GPU? I'm at a loss here.. New psu, New motherboard, New processor, hard drive and GPU only things left..

 

[tsnor]

Thought yout showed earlier that it was ram ... "So i tried running it with 2 of the 4 ram sticks, worked fine, no more issues,..."

 

[Morizan]

That is what I thought.. even the ram was replaced, I switched the reset switch over to power for the case and had no issues the entire day yesterday, so that's what it was the whole time..